PCB Failure Analysis – Dealing with Burnt and Mangled Boards
Even in the best-case scenarios, PCB failure analysis can be a challenging undertaking. Copper interconnects, integrated circuits, and discrete components are tightly packed into multilayer rat’s nests on modern printed circuit boards. A single fault can often be isolated by a single solder splash, a single incorrectly registered through, or a single fractured copper trace. This can be a difficult procedure that takes hours of testing and isolation before the source of failure is eventually identified. To put it mildly, this operation is strenuous, but the difficulty is frequently exacerbated by the fact that the device to be examined is little more than a twisted, blackened chunk of burned PCB material.
Burnt PCB failure analysis tasks could be among the most challenging ones to take on. The charred remains of a circuit board not only give off a beautiful smell of smoky creosote, but the failed sample is frequently exceedingly delicate, making any form of isolation procedures or probing challenging at best. The best that an analyst can do is locate the point where the incendiary event began because, in many circumstances, the defect itself will have been consumed in the blaze. In many situations, the device’s history rather than any one piece of the investigation may provide the key to unlocking the enigma of the issue.
Read more: PCB Failure Analysis: The Tools, Techniques, and Theory
In a project Infinita lab worked on, a heavily burned TV remote control was evaluated to show how examination of a burnt PCB might be influenced by a device’s history. A thorough examination of the device appeared to point to an external source of ignition because the charred section of the circuit board did not appear to transport much power and lacked any components that were especially likely to fail so disastrously. The initial observations did not begin to make sense until the client revealed that the remote control may have been placed in a microwave oven in an effort to dry it off after it had been exposed to moisture. In order to establish that the microwave was the cause of the failure, Infinita lab bought a microwave, put a similar remote inside, and used “Cooking for Engineers” to determine the ideal microwave duration for a faulty circuit board (best served with a light caramel sauce). Following a brief delay, the microwave’s remote was taken out and found to have damage that was strikingly identical to that of the malfunctioning appliance.
Finding the root cause problem can often be extremely challenging, if not impossible, depending on the circumstances of any occurrence that resulted in a burned circuit board. Yet with a complete and thorough history, it is much easier to pinpoint the main reason for failure.
